For many years, internal combustion engines used by vehicles have generally relied on spin-on type oil filters for lubricating oil. These filters are periodically changed and must be disposed of. In the past lubricating oil filters were disposed of in landfills, a practice now forbidden because spin-on housings and filter media contain lubricating oil which can contaminate the soil and ground water. It is therefore the current practice to disposed of these filters in other ways.
Since spin-on filters necessarily have cylindrical housings, filter media is most conveniently annular which is not necessarily the best configuration for the filter if the filter media must be removed. This is because the axis of a spin-on type filter necessarily projects from the engine block, thus consuming additional lateral space. In order to remove the annular filter media without removing its canister, there must be space provided for both the axial extent of the canister and the axial extent of the filter media. Accordingly, the canister must be removed, opened and reclosed with a new annular filter before it is replaced.
Moreover, it is not possible to check the condition of the filter media of disposable spin-on filters, nor is it convenient to sample either filtered or unfiltered liquid.
Additionally, since the lubricating oil normally flows from an annular space external the filter media to a hollow cylindrical space within the filter media, tapping the central space within the filter media with a probe to obtain technical information (such as pressure within the filter media and the condition of just filtered oil) presents a challenge since such probes must penetrate both the housing and the closed end of the filter element of which the filter media is an integral part.
It is also preferable to be able to open the housing containing the filter element without having a portion of the housing still connected to the engine.
In view of these considerations, there is a need for oil filter configurations which address the current requirements that used filter media be recycled in a way that does not endanger the environment, while having a configuration which is conveniently mounted with respect to space available in a vehicle having an engine, while providing convenient access for inspecting the filter media and lubrication oil, and for mounting monitoring probes.